65644240 has 60 divisors (see below), whose sum is σ = 161149284. Its totient is φ = 24864768.

The previous prime is 65644223. The next prime is 65644283. The reversal of 65644240 is 4244656.

It can be written as a sum of positive squares in 2 ways, for example, as 42719296 + 22924944 = 6536^2 + 4788^2 .

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27744 + ... + 30016.

Almost surely, 2^65644240 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 65644240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (80574642).

65644240 is an abundant number, since it is smaller than the sum of its proper divisors (95505044).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

65644240 is a wasteful number, since it uses less digits than its factorization.

65644240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2324 (or 2299 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 31.

The square root of 65644240 is about 8102.1133045644. The cubic root of 65644240 is about 403.3965765334.

Adding to 65644240 its reverse (4244656), we get a palindrome (69888896).

The spelling of 65644240 in words is "sixty-five million, six hundred forty-four thousand, two hundred forty".